Display device

ABSTRACT

A display device is disclosed. The display device includes a housing, a roller disposed in the housing, a display unit configured to be wound around or unwound from the roller, a foldable link having a first side pivotably coupled to the housing and a second side pivotably coupled to an upper part of the display unit, a motor disposed in the housing and configured to drive a pivoting movement of the foldable link such that the foldable link is extended out of or retracted into the housing, a fulcrum disposed adjacent to the first side of the foldable link, a lever extending in a longitudinal direction of the housing and pivotably mounted on the fulcrum and comprising a first side and a second side oppositely positioned with respect to the fulcrum, and an elastic member coupled to the second side of the lever, when the foldable link is retracted into the housing the foldable link contacts the first side of the lever to cause the lever to pivot about the fulcrum.

CROSS-REFERENCE TO RELATED APPLICATION

Pursuant to 35 U.S.C. § 119, this application claims the benefit of anearlier filing date and right of priority to International ApplicationNo. PCT/KR2019/014138, filed on Oct. 25, 2019, the contents of which arehereby incorporated by reference herein its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to a display device.

2. Description of the Related Art

As the information society has developed, the demand for display devicesis increasing in various forms, and accordingly, in recent years,various display devices such as a liquid crystal display (LCD), plasmadisplay panel (PDP), electroluminescent display (ELD), vacuumfluorescent display (VFD), and the like have been studied and used.

There among, a display device using an organic light emitting diode(OLED) has excellent luminance and viewing angle characteristics incomparison with a liquid crystal display device and does not require abacklight unit, thereby being implemented in an ultrathin type.

In addition, a flexible display panel can be bent or wound around aroller. The flexible display panel may be used to implement a displaydevice that unfolds on a roller or winds around the roller. There is anecessity for many studies on a structure for winding a flexible displaypanel around a roller or unwinding the flexible display panel from theroller.

SUMMARY OF THE INVENTION

It is an object of the present disclosure to solve the above and otherproblems.

It is another object of the present disclosure to provide a displaydevice capable of reducing load at the time of initial driving forunwinding a display panel from a roller.

It is another object of the present disclosure to provide a displaydevice capable of reducing initial driving force at the time of erectinga link.

It is a further object of the present disclosure to provide a displaydevice capable of reducing impact at the time of seating the link.

In accordance with an aspect of the present disclosure, the above andother objects can be accomplished by the provision of a display deviceincluding a housing; a roller disposed in the housing; a display unitconfigured to be wound around or unwound from the roller; a foldablelink having a first side pivotably coupled to the housing and a secondside pivotably coupled to an upper part of the display unit; a motordisposed in the housing and configured to drive a pivoting movement ofthe foldable link such that the foldable link is extended out of orretracted into the housing; a fulcrum disposed adjacent to the firstside of the foldable link; a lever extending in a longitudinal directionof the housing and pivotably mounted on the fulcrum and comprising afirst side and a second side oppositely positioned with respect to thefulcrum; and an elastic member coupled to the second side of the lever,when the foldable link is retracted into the housing the foldable linkcontacts the first side of the lever to cause the lever to pivot aboutthe fulcrum.

In accordance with another aspect of the present disclosure, thefoldable link may include a lower link having one side pivotablyconnected to the housing; and an upper link having one side pivotablyconnected to the lower link and the other side pivotably connected tothe upper part of the display unit, and the lower link may contact thefirst side of the lever when the foldable link is retracted into thehousing.

In accordance with another aspect of the present disclosure, the fulcrummay include: a lever base coupled to the housing; a first supportconfigured to support a first shaft; and a second support spaced apartfrom the first support and configured to support a second shaft parallelto the first shaft, the lever may be pivotably mounted at the firstshaft of the first support, and the elastic member may be coupled to thesecond shaft of the second support and the second side of the lever.

In accordance with another aspect of the present disclosure, the levermay include: a middle region coupled to the first shaft of the firstsupport; a first body extending from the middle region toward a mountingposition of the lower link; a second body extending from the middleregion opposite the first body; a first fork formed at a distal end ofthe first body; a second fork formed at a distal end of the second body;a roller shaft extending across the first fork; and a roller positionedon the roller shaft so as to be rotatable on the roller shaft.

In accordance with another aspect of the present disclosure, the rollermay include a urethane material.

In accordance with another aspect of the present disclosure, the firstbody and second body may be angled in an upward direction, and theelastic member may be an extension spring.

In accordance with another aspect of the present disclosure, the elasticmember may be extended when the foldable link is retracted into thehousing and may be contracted when the foldable link is extended out ofthe housing.

In accordance with another aspect of the present disclosure, a distancebetween the prongs of the first fork may be greater than a distancebetween prongs of the second fork.

In accordance with another aspect of the present disclosure, the motormay include a rotary encoder configured to sense angular displacement ofa driving shaft of the motor, and the display device may further includea controller configured to control the motor based on information aboutthe angular displacement of the driving shaft acquired from the rotaryencoder.

In accordance with another aspect of the present disclosure, the displaydevice may further include: a first gear fixed to a driving shaft of themotor; and a second gear fixed to the lower link and comprising a rotaryshaft aligned with a pivot shaft of the lower link, the second gear maybe engaged with the first gear.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIGS. 1 to 34 are views showing examples of a display device accordingto embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Description will now be given in detail according to exemplaryembodiments disclosed herein, with reference to the accompanyingdrawings. For the sake of brief description with reference to thedrawings, the same or equivalent components may be denoted by the samereference numbers, and description thereof will not be repeated.

In general, suffixes such as “module” and “unit” may be used to refer toelements or components. Use of such suffixes herein is merely intendedto facilitate description of the specification, and the suffixes do nothave any special meaning or function.

In the present disclosure, that which is well known to one of ordinaryskill in the relevant art has generally been omitted for the sake ofbrevity. The accompanying drawings are used to assist in easyunderstanding of various technical features and it should be understoodthat the embodiments presented herein are not limited by theaccompanying drawings. As such, the present disclosure should beconstrued to extend to any alterations, equivalents and substitutes inaddition to those which are particularly set out in the accompanyingdrawings.

It will be understood that although the terms first, second, etc. may beused herein to describe various elements, these elements should not belimited by these terms. These terms are only used to distinguish oneelement from another.

It will be understood that when an element is referred to as being“connected with” another element, there may be intervening elementspresent. In contrast, it will be understood that when an element isreferred to as being “directly connected with” another element, thereare no intervening elements present.

A singular representation may include a plural representation unlesscontext clearly indicates otherwise.

Referring to FIG. 1, a display device 100 may include a display unit 20and a housing 30. The housing 30 may have an internal space formedtherein. At least a portion of the display unit 20 may be located insidethe housing 30. At least a portion of the display unit 20 may be locatedoutside the housing 30. The display unit 20 may display an image on thefront surface thereof.

The direction parallel to the longitudinal direction of the housing 30may be referred to as a first direction DR1. The first direction DR1 maybe parallel to a +x axis direction or a −x axis direction. The +x axisdirection may be referred to as a rightward direction. The −x axisdirection may be referred to as a leftward direction. The direction inwhich the display unit 20 displays an image may be referred to as a +zaxis, a forward direction, or the front. The direction opposite thedirection in which the display unit 20 displays an image may be referredto as a −z axis, a rearward direction, or the rear. A third directionDR3 may be parallel to the +z axis direction or the −z axis direction.The direction parallel to the height direction of the display device 100may be referred to as a second direction DR2. The second direction DR2may be parallel to a +y axis direction or a −y axis direction. The yaxis direction may be referred to as an upward direction. The −y axisdirection may be referred to as a downward direction. The thirddirection DR3 may be a direction perpendicular to the first directionDR1 and/or the second direction DR2.

The first direction DR1 and the second direction DR2 may be collectivelyreferred to as a horizontal direction. In addition, the third directionDR3 may be referred to as a vertical direction.

A leftward-rightward direction LR may be parallel to the first directionDR1, and an upward-downward direction UD may be parallel to the seconddirection DR2.

Referring to FIG. 2, the display unit 20 may be entirely located insidethe housing 30. At least a portion of the display unit 20 may be locatedoutside the housing 30. The degree to which the display unit 20 isexposed to the outside of the housing 30 may be adjusted as necessary.

Referring to FIG. 3, a display panel 10 may be flexible. For example,the display panel 10 may be an organic light emitting display (OLED).

The display panel 10 may have a front surface for displaying an image.The display panel 10 may have a rear surface facing the front surface.The front surface of the display panel 10 may be covered with a lighttransmissive material. For example, the light transmissive material maybe glass, resin, or plastic.

A plate 11 may be coupled to the rear surface of the display panel 10.The plate 11 may be coupled, fastened or attached to the rear surface ofthe display panel 10. The plate 11 may include a metal material. Theplate 11 may be referred to as a module cover 11, a cover 11, a displaypanel cover 11, or a panel cover 11.

A resin layer 14 may be coupled to the rear surface of the plate 11. Theresin layer 14 may cover the plate 11. The plate 11 may not be exposedoutside due to the resin layer 14.

Referring to FIG. 4, the plate 11 may include a plurality of holes 12.The plate may include a region in which the holes 12 are formed andregions 11 f, 11 g, and 11 h in which the holes 12 are not formed. Theregions 11 f, 11 g, and 11 h in which the holes 12 are not formed maysurround the region in which the holes 12 are formed. The regions 11 f,11 g, and 11 h in which the holes 12 are not formed may protect the edgeof the display panel 10. The holes 12 may also be referred to asopenings 12.

The first region 11 g in which the holes 12 are not formed, the regionin which the holes 12 are formed, and the second region 11 g in whichthe holes 12 are not formed may be sequentially located in theleftward-rightward direction LR of the plate 11. The width of the firstregion 11 g in the leftward-rightward direction LR may be a2. The widthof the region in which the holes 12 are formed in the leftward-rightwarddirection LR may be a1. The width of the second region 11 h in theleftward-rightward direction LR may be a3.

The third region 11 f in which the holes 12 are not formed and theregion in which the holes 12 are formed may be sequentially located inthe upward-downward direction UD. The height of the third region 11 f inthe upward-downward direction UD may be b2. The height of the region inwhich the holes 12 are formed in the upward-downward direction UD may beb1.

The third region 11 f in which the holes 12 are not formed may becoupled to a mechanical part. For example, the mechanical part may be anupper bar. The upper bar may be coupled to a link.

The holes 12 formed through the plate 11. The holes 12 may be formed bypunching the plate 11. The holes 12 may be slits 12 a and 12 b. Theslits 12 a and 12 b may extend in the leftward-rightward direction LR ofthe plate 11. The holes 12 may include relatively long slits 12 a andrelatively short slits 12 b.

Each of the relatively long slits 12 a may have a length d8 and a widthd9. Each of the relatively short slits 12 b may have a length d10 and awidth d9.

The slits 12 a and 12 b may be spaced apart from each other in theleftward-rightward direction LR of the plate 11. Neighboring slits 12 aand 12 b may be located so as to be spaced apart from each other by apredetermined distance d2.

The slits 12 a and 12 b may be spaced apart from each other in theupward-downward direction UD of the plate 11. Neighboring slits 12 a and12 b may be located so as to be spaced apart from each other by apredetermined distance d1.

In the case in which the distances d1 and d2 between the slits 12 a and12 b are decreased, the plate 11 may be easily wound or unwound. In thecase in which the distances d1 and d2 between the slits 12 a and 12 bare increased, elasticity of the plate 11 may be increased.

The display panel 10 may have a very small thickness. The display panel10 may easily wrinkle due to the small thickness thereof. The displaypanel 10 may be easily broken by external impact due to the smallthickness thereof.

The plate 11 may be fixed to the display panel 10 to increase rigidityof the display panel 10. The plate 11 may support the display panel 10,thereby preventing the display panel 10 from wrinkling.

The plate 11 may be made of a metal material that exhibits highrigidity. The plate 11 is preferably made of a material that exhibitshigh elastic strength. Since the plate 11 has the slits 12 a and 12 b,the plate 11 may be wound around or unwound from a roller 143. Since theplate 11 has the slits 12 a and 12 b, permanent deformation of the plate11 may be prevented even when the plate is wound around or unwound fromthe roller 143.

An adhesive layer 13 may be formed at the rear surface of the displaypanel 10. The adhesive layer 13 may fix the display panel 10 to theplate 11. The display panel 10, the adhesive layer 13, and the plate 12may be coupled integrally to each other so as to form a display unit,and may be wound around or unwound from the roller 143.

The slits 12 a and 12 b may be disposed in rows and columns. Odd rowsr1, r3, r5, r7, r9, r11, r13, r15, r17, r19, r21, r23, and r25 may beconstituted by the relatively long slits 12 a. The slits 12 a in the oddrows r1, r3, r5, r7, r9, r11, r13, r15, r17, r19, r21, r23, and r25 mayconstitute columns t1, t2, t3, t4, t5, t6, t7, and t8.

Even rows r2, r4, r6, r8, r10, r12, r14, r16, r18, r20, r22, and r24 maybe constituted by the relatively short slits 12 b and the relativelylong slits 12 a. The slits 12 a and 12 b in the even rows may constitutecolumns. The slits 12 a and 12 b in the even rows r2, r4, r6, r8, r10,r12, r14, r16, r18, r20, r22, and r24 may constitute columns s1, s2, s3,s4, s5, s6, s7, s8, and s9.

The relatively short slits 12 b and the relatively long slits 12 a maybe alternately disposed in the upward-downward direction UD. Therelatively short slits 12 b may be disposed at opposite sides of theeven rows r2, r4, r6, r8, r10, r12, r14, r16, r18, r20, r22, and r24 inthe leftward-rightward direction LR.

A straight line 11 that links the center c221 of a first slit 12 b 221in a 22nd row r22 and the center c222 of a second slit 12 b 222 in the22nd row r22 may pass through the centers of the other slits in the 22ndrow r22.

A straight line 12 that links the center c231 of a first slit 12 b 231in a 23rd row r23 and the center c232 of a second slit 12 b 232 in the23rd row r23 may pass through the centers of the other slits in the 23rdrow r23.

A straight line 13 that links the center c241 of a first slit 12 b 241in a 24th row r24 and the center c242 of a second slit 12 b 242 in the24th row r24 may pass through the centers of the other slits in the 24throw r24.

A straight line 14 that links the center c251 of a first slit 12 b 251in a 25th row r25 and the center c252 of a second slit 12 b 252 in the25th row r25 may pass through the centers of the other slits in the 25throw r25.

A straight line 15 that links the center c221 of an 11th slit 12 b 221in a first column s1 of the even rows r2, r4, r6, r8, r10, r12, r14,r16, r18, r20, r22, and r24 and the center c241 of a 12th slit 12 b 241in the first column s1 may pass through the centers of the other slitsin the first column s1.

A straight line 16 that links the center c231 of a 12th slit 12 b 231 ina first column t1 of the odd rows r1, r3, r5, r7, r9, r11, r13, r15,r17, r19, r21, r23, and r25 and the center c251 of a 13rd slit 12 b 251in the first column t1 may pass through the centers of the other slitsin the first column t1.

A straight line 17 that links the center c222 of an 11th slit 12 b 222in a second column s2 of the even rows r2, r4, r6, r8, r10, r12, r14,r16, r18, r20, r22, and r24 and the center c242 of a 12th slit 12 b 242in the second column s2 may pass through the centers of the other slitsin the second column s2.

A straight line 18 that links the center c232 of a 12th slit 12 b 232 ina second column t2 of the odd rows r1, r3, r5, r7, r9, r11, r13, r15,r17, r19, r21, r23, and r25 and the center c252 of a 13rd slit 12 b 252in the second column t2 may pass through the centers of the other slitsin the second column t2.

Referring to FIGS. 5 and 6, the first resin layer 14 and the plate 11may be coupled to each other through a lamination process. The plate 11may be placed on the first resin layer 14. The plate 11 and the firstresin layer 14 may be heated by a heater. A portion of the first resinlayer 14 may melt. The melted portion of the first resin layer 14 may beadhered to the plate 11. A hole 12 in the plate 11 may be filled withthe melted portion of the first resin layer 14. The plate 11 may bereceived in the first resin layer 14.

When the heated plate 11 and first resin layer 14 are cooled, the plate11 and the first resin layer 14 may be integrated. The front surface ofthe assembly of the plate 11 and the first resin layer 14 may be flat.

Referring to FIGS. 7 and 8, the adhesive layer 13 may be formed at therear surface of the display panel 10. The adhesive layer 13 may fix thedisplay panel 10 to the plate 11. Since the front surface of theassembly of the plate 11 and the first resin layer 14 is flat, theadhesive layer 13 may fix the display panel 10 to the first resin layer14.

The first resin layer 14 may be a material that exhibits high softness.For example, the first resin layer 14 may be urethane or rubber.

The display panel 10, the adhesive layer 13, the plate 11, and the firstresin layer 14 may be coupled integrally to each other so as to form adisplay unit, and may be wound around or unwound from the roller 143.

Referring to FIG. 9, the lower end of the display panel 10 may beconnected to the roller 143. The display panel 10 may be wound around orunwound from the roller 143.

The front surface of the display panel 10 may be coupled to a pluralityof source PCBs 120. The plurality of source PCBs 120 may be spaced apartfrom each other.

A source chip on film (COF) 123 may connect the display panel 10 and thesource PCBs 120. The source COF 123 may be located at the front surfaceof the display panel 10.

The roller 143 may include a first part 331 and a second part 337. Thefirst part 331 and the second part 337 may be fastened by a screw. Atiming controller board 105 may be mounted in the roller 143.

The source PCBs 120 may be electrically connected to the timingcontroller board 105. The timing controller board 105 may send digitalvideo data and timing control signals to the source PCBs 120.

A cable 117 may electrically connect the source PCBs 120 and the timingcontroller board 105. For example, the cable 117 may be a flexible flatcable (FFC). The cable 117 may extend through a hole 331 a. The hole 331a may be formed in a seating portion 379 or the first part 331. Thecable 117 may be located between the display panel 10 and the secondpart 337.

The seating portion 379 may be formed in an outer circumference of thefirst part 331. The seating portion 379 may be formed by stepping aportion of the outer circumference of the first part 331. The seatingportion 379 may form a space B. When the display unit 20 is wound aroundthe roller 143, the source PCBs 120 may be accommodated in the seatingportion 379. Since the source PCBs 120 are accommodated in the seatingportion 379, the source PCBs 120 may not be twisted or bent, anddurability may be improved.

The cable 117 may electrically connect the timing controller board 105and the source PCBs 120.

Referring to FIG. 10, a base 32 may be flat. The base 32 may extend longin the x axis direction.

A fastening portion 921 may be installed at the upper surface of thebase 32. The fastening portion 921 may be flat. The fastening portion921 may be fixed to the upper surface of the base 32. The fasteningportion 921 may be fastened to the base 32 via a fastening member SC.

A link mount 924 may be formed at the upper surface of the fasteningportion 921. The link mount 924 may be formed integrally with thefastening portion 921. The link mount 924 may include a hole 924 a. Thehole 924 a may be formed through the link mount 924 in the z axisdirection. The link mount 924 may include a wall 924 c 1 protruding inthe +z axis direction. The wall 924 c 1 may form a receiving space 924 b1. The wall 924 c 1 may be formed along the circumference of the hole924 a.

A gear mount 923 may be formed at the upper surface of the fasteningportion 921. The gear mount 923 may be formed integrally with thefastening portion 921. The gear mount 923 may be located at the rightside of the link mount 924. The gear mount 923 may be formed integrallywith the link mount 924. The gear mount 923 may include holes 923 a 1and 923 a 2. The holes 923 a 1 and 923 a 2 may be formed through thegear mount 923 in the z axis direction. The first hole 923 a 1 may belocated at the right side of the second hole 923 a 2. The gear mount 923may include walls 923 c 1 and 923 c 2 protruding in the +z axisdirection. The first wall 923 c 1 may form a first receiving space 923 b1. The first wall 923 c 1 may be formed along the circumference of thefirst hole 923 a 1. The second wall 923 c 2 may form a second receivingspace 923 b 2. The second wall 923 c 2 may be formed along thecircumference of the second hole 923 a 2. The first receiving space 923b 1 may be located at the right side of the second receiving space 923 b2.

A motor mount 922 may be formed at the upper surface of the fasteningportion 921. The motor mount 922 may be formed integrally with thefastening portion 921. The motor mount 922 may be located at the rightside of the gear mount 923. The motor mount 922 may be formed integrallywith the gear mount 923. The motor mount 922 may include a hole 922 a.The hole 922 a may be formed through the motor mount 922 in the z axisdirection. The motor mount 922 may include a wall 922 c 1 protruding inthe +z axis direction. The wall 922 c 1 may form a receiving space 922.The wall 922 c 1 may be formed along the circumference of the hole 922a.

The walls 922 c 1, 923 c 1, 923 c 2, and 924 c 1 may be connected toeach other. The receiving spaces 922 b, 923 b 1, 923 b 2, and 924 b 1may communicate with each other. A hole 921 a may be formed in the uppersurface of the fastening portion 921. The hole 921 a may be formedthrough the fastening portion 921 in the y axis direction. The hole 921a may be located at the left side of the link mount 924. The hole 921 a,the link mount 924, the gear mount 923, and the motor mount 922 may besequentially located in the x axis direction.

Referring to FIG. 11, the motor mount may include a wall protruding inthe −z axis direction. The wall may be formed along the circumference ofthe hole.

The link mount 924 may include a wall 924 c 2 protruding in the −z axisdirection. The wall 924 c 2 may form a receiving space 924 b 2. The wall924 c 2 may be formed along the circumference of the hole 924 a.

Referring to FIG. 12, a motor 800 may be fastened to the rear surface ofthe motor mount 922. The motor 800 may be fixed to the motor mount 922.A driving shaft 800 d of the motor 800 may be inserted into the hole 922a. The driving shaft 800 d may be referred to as a rotary shaft 800 d.The driving shaft 800 d of the motor 800 may be coupled to a gear 810.The gear 810 may be rotated with the driving shaft 800 d when thedriving shaft 800 d is rotated. The gear 810 may be located in thereceiving space 922 b. The wall 922 c 1 may surround the gear 810.

A guide plate 925 a 1 may be fastened to the front surface of the linkmount 924 via a fastening member SC. The guide plate 925 a 1 may befixed to the receiving space 924 b 1. The guide plate 925 a 1 mayinclude a plurality of guides 925 a 2. The guide plate 925 a 1 mayinclude a guide recess 925 a 3 formed between neighboring guides 925 a2. Lubricating oil may be applied to the guide plate 925 a 1.

A brake 800 e may be installed in the motor 800, at the front of themotor 800, or at the rear of the motor 800. In the case in which thebrake 800 e is installed at the rear of the motor 800, the driving shaft800 d may extend through the motor 800, and the motor 800 may beinstalled at the driving shaft 800 d. The brake 800 e may include a disc800 e 1 and a caliper 800 e 2. The disc 800 e 1 may be coupled to thedriving shaft 800 d. Alternatively, the disc 800 e 1 may be formedintegrally with the driving shaft 800 d. The caliper 800 e 2 may holdthe disc 800 e 1 to brake the rotation of the disc 800 e 1. The caliper800 e 2 may include a pad configured to come into contact with or beseparated from the disc 800 e 1. The pad generates frictional force tobrake the rotation of the disc 800 e 1 when contacting the disc 800 e 1.

Referring to FIG. 13, the motor 800 may be fastened to a wall 922 c 2via a fastening member SC. A guide plate 925 b 1 may be fastened to therear surface of the link mount 924 via a fastening member SC. The guideplate 925 b 1 may be fixed to the receiving space 924 b 2. The guideplate 925 b 1 may include a plurality of guides 925 b 2. The guide plate925 b 1 may include a guide recess 925 b 3 formed between neighboringguides 925 b 2.

Referring to FIG. 14, gears 810, 820, 830, and 865 may be spur gears.The gear 820 may be installed at the gear mount 923. The gear 820 may bereceived in the receiving space 923 b 1. The wall 923 c 1 may surroundthe gear 820. A rotary shaft 823 may be inserted into the hole 923 a 1.The rotary shaft 823 may be rotated relative to the gear mount 923.Alternatively, the rotary shaft 823 may be fixed to the gear mount 923.The gear 820 may be coupled to the rotary shaft 823. The gear 820 may berotated relative to the rotary shaft 823. Alternatively, the gear 820may be fixed to the rotary shaft 823. Alternatively, the gear 820 may beformed integrally with the rotary shaft 823. The gear 820 may be adouble gear. The gear 820 may include a primary gear 821 and a secondarygear 822. The rotary shaft 823 of the primary gear 821 and the rotaryshaft 823 of the secondary gear 822 may be the same. The primary gear821 and the secondary gear 822 may be integrally formed. The diameter ofthe secondary gear 822 may be greater than the diameter of the primarygear 821. The number of teeth of the secondary gear 822 may be greaterthan the number of teeth of the primary gear 821. The secondary gear 822may be engaged with the gear 810. The secondary gear 822 may be receivedin the receiving space 923 b 1. The wall 923 c 1 may surround thesecondary gear 822.

The gear 830 may be installed at the gear mount 923. The gear 830 may bereceived in the receiving space 923 b 2. The wall 923 c 2 may surroundthe gear 830. A rotary shaft 833 may be inserted into the hole 923 a 2.The rotary shaft 833 may be rotated relative to the gear mount 923.Alternatively, the rotary shaft 833 may be fixed to the gear mount 923.The gear 830 may be coupled to the rotary shaft 833. The gear 830 may berotated relative to the rotary shaft 833. Alternatively, the gear 830may be fixed to the rotary shaft 833. Alternatively, the gear 830 may beformed integrally with the rotary shaft 833. The gear 830 may be adouble gear. The gear 830 may include a primary gear 831 (see FIG. 15)and a secondary gear 832. The rotary shaft 833 of the primary gear 831and the rotary shaft 833 of the secondary gear 832 may be the same. Theprimary gear 831 and the secondary gear 832 may be integrally formed.The diameter of the secondary gear 832 may be greater than the diameterof the primary gear 831. The number of teeth of the secondary gear 832may be greater than the number of teeth of the primary gear 831. Thesecondary gear 832 may be engaged with the gear 820. The secondary gear832 may be engaged with the primary gear 821. The primary gear 831 maybe received in the receiving space 923 b 2. The wall 923 c 2 maysurround the primary gear 831.

Referring to FIG. 15, torque output from the motor 800 may betransmitted to the fourth gear 965 via the first gear 810, the secondgear 820, and the third gear 830. As the torque is transmitted to thefourth gear 965, a link 860 fastened to the fourth gear 965 may berotated or pivoted.

The first gear 810 may be engaged with the secondary gear 822 of thesecond gear 820. The number of teeth of the secondary gear 822 may begreater than the number of teeth of the first gear 810. For example, thenumber of teeth of the first gear 810 may be 14, and the number of teethof the secondary gear 822 may be 60. The gear reduction ratio (the gearratio or the reduction ratio) of the secondary gear 822 to the firstgear 810 may be 4.29. Alternatively, the gear reduction ratio (the gearratio or the reduction ratio) of the secondary gear 822 to the firstgear 810 may be 3 to 6.

The primary gear 821 of the second gear 820 may be engaged with thesecondary gear 832 to the third gear 830. The number of teeth of thesecondary gear 832 may be greater than the number of teeth of theprimary gear 821. For example, the number of teeth of the primary gear821 may be 15, and the number of teeth of the secondary gear 832 may be70. The gear reduction ratio of the secondary gear 832 to the primarygear 821 may be 4.67. Alternatively, the gear reduction ratio of thesecondary gear 832 to the primary gear 821 may be 3 to 6.

The primary gear 831 of the third gear 830 may be engaged with thefourth gear 865. The number of teeth of the fourth gear 865 may begreater than the number of teeth of the primary gear 831. For example,the number of teeth of the fourth gear 865 may be 26, and the number ofteeth of the primary gear 831 may be 12. The gear reduction ratio of thefourth gear 865 to the primary gear 831 may be 2.17. Alternatively, thegear reduction ratio of the fourth gear 865 to the primary gear 831 maybe 1.5 to 3.

The gear reduction ratio of the fourth gear 865 to the first gear 810may be the product of the gear reduction ratio of the second gear 820 tothe first gear 810, the gear reduction ratio of the third gear 830 tothe second gear 820, and the gear reduction ratio of the fourth gear 865to the third gear 830. For example, The gear reduction ratio of thefourth gear 865 to the first gear 810 may be 4.29×4.67×2.17=43.33. Thefirst gear 810 to the fourth gear 865 may amplify torque of the motor800, thereby rotating or pivoting the link 860.

For example, the diameter of the first gear 810 may be 11.5 mm, thediameter of the primary gear 821 of the second gear 820 may be 11.5 mm,the diameter of the secondary gear 822 of the second gear 820 may be57.5 mm, the diameter of the primary gear 831 of the third gear 830 maybe 14.25 mm, the diameter of the secondary gear 832 of the third gear830 may be 67.5 mm, and the diameter of the fourth gear 865 may be 39mm.

For example, the diameter of the first gear 810 may be 14 mm, thediameter of the primary gear 821 of the second gear 820 may be 14 mm,the diameter of the secondary gear 822 of the second gear 820 may be 60mm, the diameter of the primary gear 831 of the third gear 830 may be 18mm, the diameter of the secondary gear 832 of the third gear 830 may be70 mm, and the diameter of the fourth gear 865 may be 42 mm.

For example, the diameter of the first gear 810 may be 16 mm, thediameter of the primary gear 821 of the second gear 820 may be 16 mm,the diameter of the secondary gear 822 of the second gear 820 may be 62mm, the diameter of the primary gear 831 of the third gear 830 may be 21mm, the diameter of the secondary gear 832 of the third gear 830 may be72 mm, and the diameter of the fourth gear 865 may be 45 mm.

Referring to FIG. 16, a first gear 810 a may be a worm gear. A secondarygear 822 a of a second gear 820 a may be a worm wheel gear. As the wormgear and the worm wheel gear are applied, the gear reduction ratio of tothe secondary gear 822 a to the first gear 810 a may be greatlyincreased. At this time, the gear reduction ratio may mean the number ofrevolutions of the first gear 810 a while the secondary gear 822 a makesone revolution. In the case in which a bevel gear is applied, the motor800 may be installed in a direction parallel to the x axis.

Referring to FIG. 17, a first gear 810 b and a secondary gear 822 b of asecond gear 820 b may be bevel gears. In the case in which a worm gearand a worm wheel gear are applied, the motor 800 may be installed in adirection parallel to the x axis.

Referring to FIG. 18, a lower link 912 may be fastened to the frontsurface of the link 860 via a fastening member SC2. The lower link 912may be fixed to the front surface of the link 860. Alternatively, thelower link 912 and the link 860 may be integrally formed. A cover 926may be fastened to the front surface of a mount 920 via a fasteningmember SC. The cover 926 may cover the gears 810, 820, 830, and 885.

Referring to FIG. 19, a right assembly RA may include a mount 920, acover 926, a motor 800, gears 810, 820, 830, and 885, or a link 912RL.The link 912RL may include a lower link 912, an upper link 911, or ajoint 913. The link 912RL may be referred to as a foldable link 912RL, alift 912RL, a lift assembly 912RL, a foldable lift 912RL, or a foldablelift assembly 912RL.

A left assembly LA may include the same components as the right assemblyRA. The left assembly LA and the right assembly RA may be symmetrical.The left assembly LA may include a mount 920L, a cover 926L, a motor800L, gears, or a link 912LL. The link 912LL may include a lower link912L, an upper link 911L, or a joint 913L. The link 912LL may bereferred to as a foldable link 912LL, a lift 912LL, a lift assembly912LL, a foldable lift 912LL, or a foldable lift assembly 912LL. Thelinks 912RL and 912LL may be folded or unfolded.

A first base 31 may be flat. The first base 31 may face a second base32. The first base 31 may be located under the second base 32. A support35 may be located between the first base 31 and the second base 32. Thesupport 35 may be fastened to the first base 31 via a fastening member.The support 35 may be fastened to the second base 32 via a fasteningmember. The roller 143 may be installed at the first base 31. The roller143 may be located between the first base 31 and the second base 32. Aportion of the display unit 20 may be wound around the roller 143, and aportion of the display unit 20 may be unwound from the roller 143. Theportion of the display unit 20 unwound from the roller 143 may extendupwards.

Referring to FIG. 20, a gear 912 a may be formed at the upper end of thelower link 912. Alternatively, the gear 912 a may be coupled to theupper end of the lower link 912. Alternatively, the gear 912 a may befixed to the upper end of the lower link 912. Alternatively, the gear912 a may be formed integrally with the lower link 912. A gear 911 a maybe formed at the lower end of the upper link 911. Alternatively, thegear 911 a may be coupled to the lower end of the upper link 911.Alternatively, the gear 911 a may be fixed to the lower end of the upperlink 911. Alternatively, the gear 911 a may be formed integrally withthe upper link 911. The gears 912 a and 911 a may be engaged with eachother. The gears 911 a and 912 a may be rotated relative to a first part913 a. The lower link 912 may be referred to as an arm 912.

Referring to FIG. 21, a second part 913 b may be fastened to the firstpart 913 a via a fastening member SC. The second part 913 b may be fixedto the first part 913 a. The gears 911 a and 912 a may be rotatedrelative to the first part 913 a or the second part 913 b.

Referring to FIG. 22, the upper part of the display unit 20 may be bentrearwards. The upper part of the display unit 20 may be the portion ofthe plate 11 that is not coupled to the display panel 10. The upper partof the plate 11 bent rearwards may be referred to as a bending portion11 a or a first part 11 a. A portion connected to the bending portion 11a may be referred to as a second part 11 i. A top case 950 may belocated at the upper side of the bending portion 11 a. A gasket 954 maybe located between the top case 950 and the bending portion 11 a. Alower bar 953 may be located at the lower side of the bending portion 11a. The lower bar 953 may be referred to as a bar 953. The lower bar 953may include a horizontal portion 953 a and a vertical portion 953 b. Thegasket 954 may include a hole 954 a. The bending portion 11 a mayinclude a hole 11 b. The horizontal portion 953 a may include a hole 953e. The hole 954 a of the gasket 954, the hole 11 b of the bendingportion 11 a, and the hole 953 e of the horizontal portion 953 a mayface each other. A fastening member SC may be fastened to the top case950 through the hole 953 e of the horizontal portion 953 a, the hole 11b of the bending portion 11 a, and the hole 954 a of the gasket 954. Thevertical portion 953 b may be located so as to be perpendicular to thehorizontal portion 953 a. The vertical portion 953 b may support theplate 11. The vertical portion 953 b may face a link bracket 951. Thevertical portion 953 b may include a first coupling portion 953 c and asecond coupling portion 953 d protruding rearwards. The second couplingportion 953 d may be inserted into a bearing 955. The bearing 955 may bereferred to as a ring bearing 955. The bearing 955 may be inserted intoa hole 911 a of a first arm 911. The link bracket 951 may include afirst hole 951 a and a second hole 951 b. A fastening member SC mayextend through the first hole 951 a, and may be fastened to the firstcoupling portion 953 c. A fastening member SC may extend through thesecond hole 951 b, and may be fastened to the second coupling portion953 d. The link bracket 951 may be fixed to the lower bar 953 via thefirst hole 951 a, the first coupling portion 953 c, and the fasteningmember SC. The first arm 911 may be pivotably connected to the lower bar953 via the second coupling portion 953 d, the bearing 955, the secondhole 951 b, and the fastening member SC. In this structure, wrinkles Wor rumples W of the display unit 20 may be reduced. The upper link 911may be rotated or pivoted relative to the second coupling portion 953 dor the link bracket 951.

Referring to FIG. 23, a rear wall 950 d may extend to the lower side ofa first part 950 a. The rear wall 950 d may be referred to as a secondpart 950 d. The rear wall 950 d may cover the bending portion 11 a, thegasket 954, or the horizontal portion 953 a. A first front wall 950 bmay extend to the lower side of the first part 950 a. The first frontwall 950 b may be referred to as a third part 950 b. The first frontwall 950 b may cover the upper part of the plate 11 or the second part11 i. A second front wall 950 c may extend to the lower side of thefirst front wall 950 b. The second front wall 950 c may be referred toas a fourth part 950 c. The second front wall 950 c may cover the upperpart of the display panel 10. The second front wall 950 c may coverwrinkles W or rumples W that may be generated at the upper part of thedisplay panel 10. The thickness W5 of the first front wall 950 b may begreater than the thickness W6 of the second front wall 950 c. Thethickness W5 of the first front wall 950 b may be substantially equal tothe sum of the thickness W6 of the second front wall 950 c and thethickness of the display panel 10.

The first arm 911 may include a first part 911 b that faces the verticalportion 953 b and a second part 911 c that faces the plate 11. Thethickness W9 of the second part 911 c may be substantially equal to thesum of the thickness W7 of the vertical portion 953 b and the thicknessW8 of the first part 911 b. The second part 911 c is in contact with oradjacent to the display unit 20, whereby the display unit 20 may bestably supported.

Referring to FIG. 24, the roller 143 may be installed at a mount 36. Themount 36 may be installed at the base 31. The mount 36 may be installedat one end and the other end of the roller 143 in the longitudinaldirection (x axis direction). The roller 143 may be installed betweenmounts 36. The roller 143 may be rotated relative to the mount 36. A hub278 may be installed at the mount 36. The mount 36 may be locatedbetween the roller 143 and the hub 278. The hub 278 may be coupled orfixed to one end of the roller 143. The hub 278 may be formed integrallywith the roller 143. As the roller 143 is rotated, the hub 278 may berotated. The rotational speed of the roller 143 may be equal to therotational speed of the hub 278.

A rotary shaft 315 may be installed at the mount 36. The rotary shaft315 may be rotated relative to the mount 36. A spring 314 may be woundaround the rotary shaft 315. The spring 314 may be a constant forcespring. The spring 314 may be wound around the rotary shaft 315 aplurality of times. One end of the spring 314 may be fixed to the rotaryshaft 315. The other end of the spring 314 may be fixed to the hub 278.The spring 314 may extend towards the hub 278, and may be wound aroundor unwound from the circumference of the hub 278. The spring 314 may bewound around or unwound from the rotary shaft 315, and may providerestoring force to the hub 278. The restoring force may be formed bywhich the spring 314 is wound around the rotary shaft 315. A guide 316may guide winding or unwinding of the spring 314 around or from therotary shaft 315. When the spring 314 is wound around or unwound fromthe rotary shaft 315, the rotational direction of the rotary shaft 315and the rotational direction of the hub 278 may be the same.

The rotary shaft 315 may be located lower than the hub 278 by a distanceCSD in the y axis direction. In the case in which the rotary shaft 315is located lower than the hub 278, greater force may be transmitted tothe hub 278 than in the case in which the rotary shaft 315 is locatedlevel with or higher than the hub 278. Due to restoring force that thespring 314 provides to the hub 278, the display unit 20 may be woundaround the roller 143.

Referring to FIG. 25, in the case of a conventional torsion spring,torque applied thereto may be increased as the number of revolutions isincreased, as shown by a dotted line. In the case of the spring 314,torque applied thereto may be uniform when the number of revolutionsexceeds a predetermined value, as shown by a solid line. Variation intorque necessary to wind the display unit 20 around the roller 143 maynot be great, compared to the number of times that the display unit 20is wound around the roller 143. In the case in which the constant forcespring is applied to acquire uniform torque, therefore, it is possibleto stably drive the roller 143.

Referring to FIG. 26, a fulcrum 710 may include a lever base 711, afirst support 712, and a second support 713. The lever base 711 may bemounted on the base 32 (see FIG. 12). The lever base 711 may have afirst support mount 710 a and a second support mount 710 b. The firstsupport mount 710 a may protrude toward the upper side of the lever base711, and may have an axial hole. The second support mount 710 b mayprotrude toward the upper side of the lever base 711, and may have anaxial hole spaced apart from the first support mount 710 a in the stateof being parallel thereto.

The first support 712 may be inserted into the first support mount 710a. The first support 712 may be referred to as a first support shaft712. The second support 713 may be inserted into the second supportmount 710 b. The second support 713 may be referred to as a secondsupport shaft 713. The height of the first support mount 710 a may begreater than the height of the second support mount 710 b. That is, thismeans that the position of the first support 712 may be higher than theposition of the second support 713 with respect to the lever base 711.

A lever 720 may include a center 721, a first bar 722, a second bar 725,a first fork 723 and 724, and a second fork 726 and 727. The lever 720may be generally bent in the form of V. The center 721 may be pivotablycoupled to the first support 712. The first bar 722 may extend long fromone side of the center 721, and the second bar 725 may extend long fromthe other side of the center 721. The first bar 722 may be opposite thesecond bar 725 with respect to the center 721. The length of the firstbar 722 may be greater than the length of the second bar 725.

The first fork 723 and 724 may be formed so as to extend long from thefirst bar 722 in a direction far away from the center 721. For example,the first fork 723 and 724 may have two blades 723 and 724. The secondfork 726 and 727 may be formed so as to extend long from the second bar725 in a direction far away from the center 721. For example, the secondfork 726 and 727 may have two blades 726 and 727. The length of theblades 726 and 727 of the second fork may be greater than the length ofthe blades 723 and 724 of the first fork. The distance between theblades 726 and 727 of the second fork may be less than the distancebetween the blades 723 and 724 of the first fork.

A roller shaft 730 may be inserted into the distal ends of the blades723 and 724 of the first fork. A roller 760 may be fitted on the rollershaft 730. For example, the roller 760 may include a urethane material.A holder shaft 740 may be inserted into the distal ends of the blades726 and 727 of the second fork. One end of a spring 750 may be caught bythe second support 713, and the other end of the spring 750 may becaught by the holder shaft 740. For example, the spring 750 may be anextension spring.

Referring to FIGS. 27 and 28, the height of the top case 950 in the yaxis direction may be the maximum. In the case in which the height ofthe top case 950 in the y axis direction is the maximum, the angle Eformed by the lower links 912 and 912L and the upper links 911 and 911Lmay be the maximum. For example, the angle E may be 180 degrees. In thecase in which the height of the top case 950 in the y axis direction isthe maximum, the display unit 20 may be in the state of being maximallyunwound from the roller 143. In the case in which the height of the topcase 950 in the y axis direction is the maximum, the roller 760 of thelever 700 may not contact the links 860 and 860L.

Referring to FIG. 29, the motors 800 and 800L may rotate or pivot thelower links 912 and 912L.

As the motors 800 and 800L rotate or pivot the lower links 912 and 912Lin the direction in which the lower link is erected relative to the base32, the angle D formed by the lower links 912 and 912L and the upperlinks 911 and 911L may increase. As the motors 800 and 800L rotate orpivot the lower links 912 and 912L in the direction in which the lowerlink is erected relative to the base 32, the angle formed by the lowerlinks 912 and 912L and the base 32L may increase. As the motors 800 and800L rotate or pivot the lower links 912 and 912L in the direction inwhich the lower link is erected relative to the base 32, the top case950 may move in the +y axis direction. As the motors 800 and 800L rotateor pivot the lower links 912 and 912L in the direction in which thelower link is erected relative to the base 32, the display unit may beunwound from the roller.

As the motors 800 and 800L rotate or pivot the lower links 912 and 912Lin the direction opposite the direction in which the lower link iserected relative to the base 32, the angle D formed by the lower links912 and 912L and the upper links 911 and 911L may decrease. As themotors 800 and 800L rotate or pivot the lower links 912 and 912L in thedirection opposite the direction in which the lower link is erectedrelative to the base 32, the angle D formed by the lower links 912 and912L and the base 32L may increase. As the motors 800 and 800L rotate orpivot the lower links 912 and 912L in the direction opposite thedirection in which the lower link is erected relative to the base 32,the top case 950 may move in the −y axis direction. As the motors 800and 800L rotate or pivot the lower links 912 and 912L in the directionopposite the direction in which the lower link is erected relative tothe base 32, the display unit may be wound around the roller.

As the lower links 912 and 912L are rotated or pivoted in the directionin which the lower link is erected, the distance between the joints 913and 913L may increase. As the lower links 912 and 912L are rotated orpivoted in the direction opposite the direction in which the lower linkis erected, the distance between the joints 913 and 913L may decrease.

Referring to FIGS. 30 and 31, the height of the top case 950 in theyaxis direction may be the minimum. In the case in which the height ofthe top case 950 in the y axis direction is the minimum, the angle Gformed by the lower links 912 and 912L and the upper links 911 and 911Lmay be the minimum. In the case in which the height of the top case 950in the y axis direction is the minimum, the display unit 20 may be inthe state of being maximally wound around the roller 143. In the case inwhich the height of the top case 950 in they axis direction is theminimum, the roller 760 of the lever 700 may contact the links 860 and860L. As the height of the top case 950 in they axis directiondecreases, the links 860 and 860L may push the roller 760 of the lever700, the lever 700 may be pivoted about the first support 712. As thelever 720 is rotated or pivoted about the first support 712, the heightof the roller 760 of the lever 700 may decrease, and the height of theholder shaft 740 of the lever 720 may increase.

For example, a change may be made from the state in which the height ofthe roller 760 of the lever 700 is greater than the height of the holdershaft 740 of the lever 720 to the state in which the height of theroller 760 of the lever 700 is less than the height of the holder shaft740 of the lever 720. As a result, the length of the spring 750 mayincrease, and the lever 720 may provide the links 860 and 860L withforce by which the height of the roller 760 of the lever 700 is restoredto the state in which the height of the roller 760 of the lever 700 isgreater than the height of the holder shaft 740 of the lever 720.

Consequently, the lever 720 may provide erecting force to the links 860and 860L at the time of initial driving (erecting operation) of thelinks 860 and 860L, and may provide damping force to the links 860 and860L at the time of final driving (folding operation) of the links 860and 860L.

Referring to FIG. 32, the display device 100 may include an interfaceunit 1200 connected to an external device. The interface unit 1200 maybe connected to an external power source 1300, and may receive powerfrom the external power source 1300. A processor 1000 may distributepower to respective components. The processor 1000 may be referred to asa control unit 1000 or a controller 1000.

A memory 1100 may store various data necessary to operate the displaydevice 100, such as programs for processing or control of the processor1000. The memory 1100 may store various application programs orapplications driven in the display device 100.

The processor 1000 may control the operation of the left assembly LA andthe right assembly RA. Driving of the left assembly LA and the drivingof the right assembly RA must be performed in a symmetrical fashion suchthat the display unit 20 is smoothly wound around or unwound from theroller 143.

The processor 1000 may simultaneously control the motors 800 and 800L.The processor 1000 may control the rotational amounts, rotationalspeeds, or rotational directions of the driving shafts 800 d and 800Ldof the motors 800 and 800L. The processor 1000 may perform control suchthat the rotational directions of the driving shafts 800 d and 800Ld ofthe motors 800 and 800L are opposite each other. The processor 1000 mayperform control such that the rotational speeds of the driving shafts800 d and 800Ld of the motors 800 and 800L are the same. The processor1000 may perform control such that the rotational amounts of the drivingshafts 800 d and 800Ld of the motors 800 and 800L are the same. Ascontrol is performed such that the rotational amounts or the rotationalspeeds of the driving shafts 800 d and 800Ld of the motors 800 and 800Lare the same, the rotational amounts or pivoting amounts of the links911 and 911L may be the same. As control is performed such that therotational amounts or the rotational speeds of the driving shafts 800 dand 800Ld of the motors 800 and 800L are the same, the links 911 and911L may be operated in a symmetrical fashion. As control is performedsuch that the rotational amounts or the rotational speeds of the drivingshafts 800 d and 800Ld of the motors 800 and 800L are the same, the topcase 950 may move upwards and downwards in the y axis direction whileremaining horizontal.

The processor 1000 may sense the rotational amount, rotational speed, orrotational direction of the motor 800L of the left assembly LA through aposition sensor 800Lb. The position sensor 800Lb may include at leastone of a PCB 870 or a sensor 890. The rotational amount may mean angulardisplacement. The rotational speed may mean angular velocity. Theprocessor 1000 may sense the rotational amount, rotational speed, orrotational direction of the motor 800 of the right assembly RA through aposition sensor 800 b. The position sensor 800 b may include at leastone of a PCB 870 or a sensor 890. The motors 800 and 800L may havebrakes 800 e and 800Le for braking the driving shafts 800 d and 800Ld.The processor 1000 may control operation of the brakes 800 e and 800Lein order to reduce the rotational speeds of the motors 800 and 800L orto stop driving of the motors 800 and 800L.

In the case in which the rotational amount of one of the motors 800 and800L is larger, the processor 1000 may decrease the rotational speed ofthe motor having the larger rotational amount, or may stop driving ofthe motor having the larger rotational amount. Alternatively, in thecase in which the rotational amount of one of the motors 800 and 800L islarger, the processor 1000 may increase the rotational speed of themotor having the smaller rotational amount.

In the case in which the rotational speed of one of the motors 800 and800L is higher, the processor 1000 may decrease the rotational speed ofthe motor having the higher rotational speed, or may stop driving of themotor having the higher rotational speed. Alternatively, in the case inwhich the rotational speed of one of the motors 800 and 800L is higher,the processor 1000 may increase the rotational speed of the motor havingthe lower rotational speed.

Referring to FIG. 33, the motors 800 and 800L may have encoders 800Laand 800 a for sensing rotational amounts, rotational speeds, orrotational directions of the driving shafts 800 d and 800Ld. Theprocessor 100 may receive information about the rotational amounts,rotational speeds, or rotational directions of the driving shafts 800 dand 800Ld of the motors 800 and 800L through the encoders 800La and 800a. The motors 800 and 800L may have brakes 800 e and 800Le for brakingrotation of the driving shafts 800 d and 800Ld. The processor maycontrol operation of the brakes 800 e and 800Le in order to reduce therotational speeds of the motors 800 and 800L or to stop driving of themotors 800 and 800L.

In the case in which the rotational amount of one of the motors 800 and800L is larger, the processor 1000 may decrease the rotational speed ofthe motor having the larger rotational amount, or may stop driving ofthe motor having the larger rotational amount. Alternatively, in thecase in which the rotational amount of one of the motors 800 and 800L islarger, the processor 1000 may increase the rotational speed of themotor having the smaller rotational amount.

In the case in which the rotational speed of one of the motors 800 and800L is higher, the processor 1000 may decrease the rotational speed ofthe motor having the higher rotational speed, or may stop driving of themotor having the higher rotational speed. Alternatively, in the case inwhich the rotational speed of one of the motors 800 and 800L is higher,the processor 1000 may increase the rotational speed of the motor havingthe lower rotational speed.

Referring to FIG. 34, each of the motors 800 and 800L may be a stepmotor, a stepper motor, or a stepping motor. The processor 1000 maysimultaneously control the motors 800 and 800L. The processor 1000 maycontrol the rotational amounts, rotational speeds, or rotationaldirections of the driving shafts 800 d and 800Ld of the motors 800 and800L. The rotational amounts of the driving shafts 800 d and 800Ld ofthe motors 800 and 800L may mean the number of steps that the drivingshafts 800 d and 800Ld are rotated. The rotational speeds of the drivingshafts 800 d and 800Ld of the motors 800 and 800L may mean the number ofsteps that the driving shafts 800 d and 800Ld are rotated per unit time.The motors 800 and 800L may have brakes 800 e and 800Le for brakingrotation of the driving shafts 800 d and 800Ld. The processor 1000 maycontrol operation of the brakes 800 e and 800Le in order to reduce therotational speeds of the motors 800 and 800L or to stop driving of themotors 800 and 800L. The processor 100 may receive information about therotational amounts, rotational speeds, or rotational directions of thedriving shafts 800 d and 800Ld of the motors 800 and 800L from themotors 800 and 800L.

In the case in which the rotational amount of one of the motors 800 and800L is larger, the processor 1000 may decrease the rotational speed ofthe motor having the larger rotational amount, or may stop driving ofthe motor having the larger rotational amount. Alternatively, in thecase in which the rotational amount of one of the motors 800 and 800L islarger, the processor 1000 may increase the rotational speed of themotor having the smaller rotational amount.

In the case in which the rotational speed of one of the motors 800 and800L is higher, the processor 1000 may decrease the rotational speed ofthe motor having the higher rotational speed, or may stop driving of themotor having the higher rotational speed. Alternatively, in the case inwhich the rotational speed of one of the motors 800 and 800L is higher,the processor 1000 may increase the rotational speed of the motor havingthe lower rotational speed.

As is apparent from the above description, a display device according tothe present disclosure has the following effects.

According to at least one of the embodiments of the present disclosure,it is possible to reduce load at the time of initial driving forunwinding a display panel from a roller.

In addition, according to at least one of the embodiments of the presentdisclosure, it is possible to reduce initial driving force at the timeof erecting a link.

In addition, according to at least one of the embodiments of the presentdisclosure, it is possible to reduce impact at the time of seating thelink.

The additional scope of applicability of the present disclosure will beapparent from the above detailed description. However, those skilled inthe art will appreciate that various modifications and alterations arepossible, without departing from the idea and scope of the presentdisclosure, and therefore it should be understood that the detaileddescription and specific embodiments, such as the preferred embodimentsof the present disclosure, are provided only for illustration.

Certain embodiments or other embodiments of the disclosure describedabove are not mutually exclusive or distinct from each other. Any or allelements of the embodiments of the disclosure described above may becombined or combined with each other in configuration or function.

For example, a configuration “A” described in one embodiment of thedisclosure and the drawings and a configuration “B” described in anotherembodiment of the disclosure and the drawings may be combined with eachother. Namely, although the combination between the configurations isnot directly described, the combination is possible except in the casewhere it is described that the combination is impossible.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the scope of the principles of thisdisclosure. More particularly, various variations and modifications arepossible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A display device comprising: a housing; a roller disposed in the housing; a display unit configured to be wound around or unwound from the roller; a foldable link having a first side pivotably coupled to the housing and a second side pivotably coupled to an upper part of the display unit; a motor disposed in the housing and configured to drive a pivoting movement of the foldable link such that the foldable link is extended out of or retracted into the housing; a fulcrum disposed adjacent to the first side of the foldable link; a lever extending in a longitudinal direction of the housing and pivotably mounted on the fulcrum and comprising a first side and a second side oppositely positioned with respect to the fulcrum; and an elastic member coupled to the second side of the lever, wherein when the foldable link is retracted into the housing the foldable link contacts the first side of the lever to cause the lever to pivot about the fulcrum.
 2. The display device according to claim 1, wherein the foldable link comprises: a lower link having one side pivotably connected to the housing; and an upper link having one side pivotably connected to the lower link and the other side pivotably connected to the upper part of the display unit, and the lower link contacts the first side of the lever when the foldable link is retracted into the housing.
 3. The display device according to claim 1, wherein the fulcrum comprises: a lever base coupled to the housing; a first support configured to support a first shaft; and a second support spaced apart from the first support and configured to support a second shaft parallel to the first shaft, wherein the lever is pivotably mounted at the first shaft of the first support, and the elastic member is coupled to the second shaft of the second support and the second side of the lever.
 4. The display device according to claim 3, wherein the lever comprises: a middle region coupled to the first shaft of the first support; a first body extending from the middle region toward a mounting position of the lower link; a second body extending from the middle region opposite the first body; a first fork formed at a distal end of the first body; a second fork formed at a distal end of the second body; a roller shaft extending across the first fork; and a roller positioned on the roller shaft so as to be rotatable on the roller shaft.
 5. The display device according to claim 4, wherein the roller comprises a urethane material.
 6. The display device according to claim 4, wherein the first body and second body are angled in an upward direction, and the elastic member is an extension spring.
 7. The display device according to claim 6, wherein the elastic member is extended when the foldable link is retracted into the housing and contracted when the foldable link is extended out of the housing.
 8. The display device according to claim 4, wherein a distance between the prongs of the first fork is greater than a distance between prongs of the second fork.
 9. The display device according to claim 1, wherein: the motor comprises a rotary encoder configured to sense angular displacement of a driving shaft of the motor, and the display device further comprises a controller configured to control the motor based on information about the angular displacement of the driving shaft acquired from the rotary encoder.
 10. The display device according to claim 2, further comprising: a first gear fixed to a driving shaft of the motor; and a second gear fixed to the lower link and comprising a rotary shaft aligned with a pivot shaft of the lower link, wherein the second gear is engaged with the first gear. 